The finger regrowth isn't a human body fact - it's a modern medicine fact. We can use pig bladder extract (been so long since I've seen the story so I might be wrong) to stimulate the regrowth of some (serious) wounds. One man had almost the entire third of his finger grown back within four weeks.

That's more than just your fingerprint, though. I figured like if you sanded them off until you get through a couple layers of skin, they'd grow back into your fingerprint's original shape. A lot of these are misleading anyways.